Can exemestane (aromatase inhibitor) or anastrozole (aromatase inhibitor) cause acne?

Exemestane and Anastrozole Can Cause Acne as a Side Effect

Yes, both exemestane and anastrozole can cause acne as a side effect, particularly in pediatric patients and adolescents, though it can occur in adults as well. 1

Mechanism of Action and Skin Effects

• Aromatase inhibitors (AIs) like exemestane and anastrozole work by inhibiting the aromatase enzyme, which converts androgens to estrogens, thereby reducing circulating estrogen levels 2
• This hormonal manipulation can lead to relative androgen predominance, which may trigger acne in some patients 1
• In clinical studies of anastrozole in adolescent boys with pubertal gynecomastia, acne was reported as one of the most frequent treatment-related adverse reactions (7% with anastrozole vs 2.7% with placebo) 1

Evidence from Clinical Studies

• FDA drug labeling specifically lists acne as a treatment-related adverse effect of anastrozole, particularly noted in pediatric populations 1
• In a randomized, double-blind, placebo-controlled study of adolescent boys, acne was the most common adverse reaction reported with anastrozole treatment 1
• In a study of girls with McCune-Albright Syndrome treated with anastrozole, acne was among the adverse reactions considered possibly related to treatment 1

Dermatologic Side Effects of Aromatase Inhibitors

• While acne is specifically documented, aromatase inhibitors can cause various skin reactions that may present 5 days to 6 months after starting treatment (median 2 months) 3
• Other reported cutaneous adverse effects include:
  • Vasculitis 4
  • Erythema nodosum 4
  • Subacute cutaneous lupus erythematosus 3, 4
  • Various rashes and dermatitis 3

Management Considerations

• For patients experiencing acne or other skin reactions while on aromatase inhibitors:
  • Topical treatments for acne may be considered for mild cases 3
  • For severe reactions, discontinuation of the aromatase inhibitor may be necessary 3, 4
  • In some cases, switching to a different aromatase inhibitor may be possible without recurrence of the skin reaction 3
  • Topical or oral corticosteroids may be required to manage more severe skin reactions 3

Clinical Implications

• When prescribing exemestane or anastrozole for breast cancer risk reduction or treatment, patients should be informed about the potential for skin reactions, including acne 5
• The risk-benefit profile should be carefully considered, especially in patients with pre-existing skin conditions 5
• Regular follow-up to monitor for dermatologic adverse effects is important, particularly during the first 6 months of treatment 3

Important Caveats

• The incidence of acne appears higher in pediatric and adolescent populations than in postmenopausal women taking these medications for breast cancer 1
• Individual susceptibility to skin reactions varies significantly 3
• Skin reactions may be more likely to occur at the original site of breast malignancy or in areas previously treated with surgery or radiotherapy 3